1956→1959 Austin-Healey 100-Six BN4
In August of 1956, the big-Healey entered regular production with a six-cylinder engine and included a pair of small occasional seats in the rear. Met with considerable criticism, it replaced the more powerful four-cylinder unit and was a heavier car.
Chassis prefix for the first cars were introduced as BN4 which denoted a 4-seat roadster. Later in production a BN6 variant of the 100-6 was introduced in March 1958 as a 2-seat roadster. This was more inline with the original 100-4’s concept and it outsold the BN4.
In 1957 a new cast-aluminum 6-port intake manifold was introduced to the model that replaced the integral head unit. With larger valves, and a higher compression power was raised from 101 to 117 bhp. It also increased the price from £762 to £817.
Roy Salvadori said “the new 6-port induction system gives her an impressive increase in punch, particularly in top from 50 to 80 mph….the Austin-Healey always had plenty of dig but now its outstanding…”
The first sixes were built at Austin’s facility at Longbridge until December 1957 when production resumed at Abington. The model was discontinued in Match of 1959, but some BN7 models, better known as the 3000 MKI, were produced with 100-6 badges.
Donald Healey was an avid racing enthusiast so the six-cylinder Healeys were almost immediately on the track. Three modified cars were entered for the 1957 12-Hours of Sebring with streamlined bodies and Weber carburetors. One of the cars finished second in class. Another attempt was made at the same race with disc-brake cars. That same year Corvette racer Dick Thompson agreed to race a 100-6 for the 1958 SCCA Championship which he won.
BMC’s Competition Department prepared UOC741 (BN4) TON792, PMO201, PMO202 and PMO203 for rally at events such as Liège-Rome-Liège, the Coupe des Alps and the Tulip Rally. They never won outright, but the results were always first or second in class.
|tags||3000, 100/6, six|
|submitted by||Richard Owen|
|type||Series Production Car|
|production years||1956 – 1959|
|built at||Abington, England|
|engine||Series C Straight-6|
|valvetrain||OHV 2 Valves / Cyl|
|displacement||2639 cc / 161.04 in³|
|bore||79.4 mm / 3.125 in|
|stroke||88.9 mm / 3.5 in|
|power||87.2 kw / 117 bhp @ 4700 rpm|
|specific output||44.33 bhp per litre|
|bhp/weight||106.17 bhp per tonne|
|torque||192.5 nm / 142 ft lbs @ 2400 rpm|
|body / frame||Steel Body over Steel Frame|
|driven wheels||Front Engine / RWD|
|curb weight||1102 kg / 2429 lbs|
|wheelbase||2337 mm / 92.0 in|
|front track||1328 mm / 52.3 in|
|rear track||1270 mm / 50.0 in|
|length||4001 mm / 157.5 in|
|width||1537 mm / 60.5 in|
|height||1270 mm / 50.0 in|
|transmission||4-Speed Manual w/Overdrive|
|gear ratios||2.93:1, 2.05:1, 1.31:1, 1.00:1|
|top speed||~185.1 kph / 115.0 mph|
|0 – 60 mph||~10.7 seconds|
|0 – 100 mph||~36.0 seconds|
|0 – 1/4 mile||~17.0 seconds|
Auction Sales History
Auction Source: 2014 Paris by RM Auctions
– This particular BN4 is a remarkably original and well optioned example
– Believed to be under 30,000 actual miles
– Original paint, interior, soft top, top boot and tonneau cover
– Car comes with radio, heater and a factory hardtop with original paint
Auction Source: 2010 Mecum at Monterey